公开(公告)号：US06674435B1

公开(公告)日：2004-01-06

申请号：US09382144

申请日：1999-08-24

申请人： Ralph E. Payne ,  Lowell Boggs

发明人： Ralph E. Payne ,  Lowell Boggs

IPC分类号： G06T1100

CPC分类号： G06F17/175 ,  G06T11/203

摘要： A printer forms an approximate of a Bezier curve as a sequence of line segments. Two parametric equations, X(t) and Y(t), are employed. Two methods can be used to evaluate the parametric equations. Both use fixed point integer arithmetic to directly calculate points along the curve which are the values of the X(t) and Y(t) equations. The first method sets the number of steps of the parametric variable are equal to an integral power of 2. This gives a predictable execution time and uses line segments to connect the points as a piecewise straight line approximation to the curve. The number of steps is set as the next higher power of 2 than an estimated length of the curve. The second method allows Y(t), the scan line variable, to change only in predetermined integer steps. The value of X(t) is evaluated for each t corresponding to the integer step in Y(t). This second method has a natural advantage, if a closed path is being decomposed as a run array rather than a collection of trapezoids. Both methods create the lines segments in natural scan line order. This is advantageous for polygon fill algorithms because it eliminates the need for edge sorting.

摘要翻译： 打印机形成Bezier曲线的近似值作为一系列线段。 采用两个参数方程X（t）和Y（t）。 两种方法可用于评估参数方程。 两者都使用固定点整数算术直接计算曲线上的点，这些点是X（t）和Y（t）方程的值。 第一种方法将参数变量的步数设置为等于2的积分功率。这给出了可预测的执行时间，并使用线段将点作为分段直线逼近来连接到曲线。 步数被设置为比曲线的估计长度更高的2倍。 第二种方法允许Y（t），扫描线变量仅在预定的整数步骤中改变。 对于与Y（t）中的整数步长对应的每个t，评估X（t）的值。 如果闭路径被分解为运行阵列而不是梯形集合，则第二种方法具有自然的优势。 两种方法都以自然扫描行顺序创建线段。 这对于多边形填充算法是有利的，因为它不需要边缘分类。

公开(公告)号：US06567182B1

公开(公告)日：2003-05-20

申请号：US09397539

申请日：1999-09-16

申请人： Suvarna Harish Kumar ,  Sadhana Gupta ,  Lowell Boggs ,  Venkat V. Easwar ,  Arunabha Ghose

发明人： Suvarna Harish Kumar ,  Sadhana Gupta ,  Lowell Boggs ,  Venkat V. Easwar ,  Arunabha Ghose

IPC分类号： G06M1500

CPC分类号： G06T11/40

摘要： This invention cures many inefficiencies with known scan conversion methods. This invention employs a edge array rather than a set linked list from an array of pointers equal in number to the number of scan lines. This invention thus eliminates storage of linked list pointers which in the prior art included many null pointers resulting in better memory utilization. es on-chip memory when employing a single chip microprocessor. This invention sorts the active edge table only at edge intersections and vertices, thus eliminating much unneeded sorting. This invention permits integrated clipping of a subject polygon by a clip polygon and forming trapezoids filling the clipped area by activating trapezoid formation at every vertex of either polygon and at every edge intersection. This process saves code space and computer processing time. This invention efficiently utilizes the resources of a multiprocessor integrated circuit by spawning of subtasks from a RISC type processor to one or more DSP type processors.

摘要翻译： 本发明通过已知的扫描转换方法固化许多低效率。 本发明采用边缘阵列而不是来自与扫描线数量相等的指针阵列的设置链表。 因此，本发明消除了链接列表指针的存储，其在现有技术中包括许多空指针，导致更好的存储器利用。 采用单芯片微处理器时的片上存储器。 本发明仅在边缘交叉点和顶点处分割活动边缘表，从而消除了不必要的分类。 本发明允许通过剪辑多边形对对象多边形进行集成剪裁，并且通过激活在任一多边形的每个顶点处和每个边缘交点处的梯形形成来填充剪切区域的梯形。 此过程可节省代码空间和计算机处理时间。 本发明通过将子任务从RISC型处理器产生到一个或多个DSP类型处理器来有效地利用多处理器集成电路的资源。